title: Improved air trapping evaluation in chest computed tomography in children with cystic fibrosis using real-time spirometric monitoring and biofeedback.
abstract: BACKGROUND
  The quality of chest Computed Tomography (CT) images in children is dependent upon a sufficient breath hold during CT scanning. This study evaluates the influence of spirometric breath hold monitoring with biofeedback software on inspiratory and expiratory chest CT lung density measures, and on trapped air (TA) scoring in children with cystic fibrosis (CF). This is important because TA is an important component of early and progressive CF lung disease.
  
  
  METHODS
  A cross sectional comparison study was completed for chest CT imaging in two cohorts of CF children with comparable disease severity, using spirometric breath hold monitoring and biofeedback software (Copenhagen (COP)) or unmonitored breath hold manoeuvres (Gothenburg (GOT)). Inspiratory-expiratory lung density differences were calculated, and TA was scored to assess the difference between the two cohorts.
  
  
  RESULTS
  Eighty-four chest CTs were evaluated. Mean (95%CI) change in inspiratory-expiratory lung density differences was 436 Hounsfield Units (HU) (408 to 464) in the COP cohort with spirometric breath hold monitoring versus 229 HU (188 to 269) in the GOT cohort with unmonitored breath hold manoeuvres (p<0.0001). The Mean TA (95%CI) score was 6.93 (6.05 to 7.82) in COP patients and 3.81 (2.89 to 4.73) in GOT (p<0.0001) patients.
  
  
  CONCLUSIONS
  In children with comparable CF lung disease, spirometric breath hold monitoring during examination yielded a large difference in lung volume between inhalation and exhalation, and allowed for a significantly greater measured change in lung density and TA score, compared to unmonitored breath hold maneuvers. This has implications to the clinical use of chest CT, especially in children with early CF lung disease.
authors.affiliation: CF Centre Copenhagen, Danish PCD & chILD Centre, Paediatric Pulmonary Service, Department of Paediatrics and Adolescent Medicine, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, Copenhagen DK-2100, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kongstad
authors.forename: Frederik F
authors.initials: FF
authors.lastname: Buchvald
authors.forename: Kent
authors.initials: K
authors.lastname: Green
authors.forename: Anders
authors.initials: A
authors.lastname: Lindblad
authors.forename: Terry E
authors.initials: TE
authors.lastname: Robinson
authors.forename: Kim G
authors.initials: KG
authors.lastname: Nielsen
mesh_terms: D000293:Adolescent; D001676:Biofeedback, Psychology; D002648:Child; D003550:Cystic Fibrosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging*; D008176:Lung Volume Measurements / Q000379:methods*; D008297:Male; D008991:Monitoring, Physiologic; D013147:Spirometry / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014797:Vital Capacity
keywords: BMI; Body mass index; Breath-hold monitoring; CF; CF lung disease; CFCT; COP; CT; Computer tomography; Copenhagen; Cystic fibrosis; Cystic fibrosis computer tomography; FEV1; FVC; Forced expiratory volume in 1s; Forced vital capacity; GOT; Gothenburg; HU; Hounsfield unit; Hounsfield units; ICC; Image quality; Intraclass correlation coefficient.; SVC; Slow vital capacity; TA; TLC; Total lung capacity; Trapped air